1. Field of the Invention
The present invention relates to a method of forming a nitride film, and more particularly, to a method of forming a nitride film including certain conductive type impurities such as n type impurities and a nitride structure formed by using the method.
2. Description of the Related Art
In general, group III nitride semiconductors may emit a broad spectrum of light covering not only an entire of visible light also ultra violet (UV) and have been in the lime light. To form light emitting diodes (LEDs) or provide a conductive substrate, it is required to group III nitride semiconductors to be formed to have a certain conductive type such as a p type and an n type and various methods have been employed. For example, an n type GaN is formed by using a metal organic chemical vapor deposition (MOCVD) method of supplying monosilane SiH4 as n type impurities together with TMG and NH3 gas at the same time.
However, since an equilibrium vapor pressure of nitrogen is very high, a nitrogen atom may be departed from a crystal when a Ga atom is substituted with a group IV element such as a Si atom that is n type impurities. Accordingly, due to the departure of the nitrogen atom, a number of defects may increases and device characteristics may be deteriorated.
To solve the problem, a method of using a group VI element such as Te as n type impurities has been tried. In the MOCVD method or an MBE method, though diethylen-Te (DETe) may be used for a Te impurity source, doping is difficult and a residue exists in a reaction chamber, thereby causing a trouble in performing a next process.
Implantation techniques for ions by using high energy is introduced by “Redistribution and activation of implanted S, Se, Te, Be, Mg, and C in GaN” J. Vac. Sci. Tchnol. A. 17 (4), July/August 1999. However, referring to FIG. 1, implanted ions may be activated when heat-treated at a temperature of at least 1200° C. Furthermore, since a GaN crystal is deteriorated in a process of implanting ions by using high energy, a heat treatment process at a temperature more than 1400° C. is required.